1. Field of the Invention
This invention relates to a piston rod seal.
More particularly the invention relates to a piston rod seal of the type comprising a plastically deformable gland adapted to surround a reciprocating piston rod which is passed through an opening in a wall separating a high pressure gas chamber from a low pressure gas chamber, means for supplying oil to the piston rod at the low pressure side of said wall, said gland being axially compressed by a spring located at the high pressure side of the wall, said gland being provided with a conical part diverging slightly from the piston rod in the direction towards the high pressure side of the seal.
2. Description of the Prior Art
A seal of this type has been disclosed in the U.S. Patent Specification No. 4,251,081. In said known device the gland is axially compressed through conical elements providing a radial, inwardly directed force on the gland towards the piston rod.
However, the piston rod--leakage along which should be prevented--is normally guided at its two ends, one of which is carrying a piston whereas the other is carrying a cross-head. The structure providing this guiding of the two piston rod ends will unavoidably allow small traverse movements of the piston rod relative to the axis of the opening in the wall through which the rod is passed. However, any traverse relative movements of the conical surfaces through which the axial force on the gland is transmitted will cause unwanted gas leakage.